A distance measuring technique has conventionally been known wherein parallax calculation is executed for an object that is included in taken images (a stereo image) taken by using a plurality of image taking parts such as a stereo camera so that a distance of such an object is calculated (see, for example, Japanese Patent Application Publication No. 2000-329852).
However, as a repetitive pattern in a lateral direction is included in a stereo image to be subjected to parallax calculation in a case of the distance measuring technique described above, a characteristic is provided such that a frequency of occurrence of an error in parallax calculation is increased.